Re: [lwip-users] lwIP performance

[Kieran Mansley]

On Fri, 2010-02-05 at 16:00 +0800, yueyue papa wrote:
> Is there configuration problem in my setup?
> 
> Why my download is only half of my upload?

You have a very small receive window (just 4 * MSS), and so the other
end can only have 4 segments in flight to you at any one time until you
ack them.  It will therefore send four segments, then wait a while to
receive the ACKs, then send more.  This waiting means lower performance.

In the other direction, the other end probably has a larger receive
window, so lwIP doesn't have to stop to wait for ACKs to give more
window space, so it can just send continually.  This means higher
performance in that direction.

Kieran